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How Do We Know God Exists? Dr. David Hogg

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Dr. Arnold interviews Dr. Hogg on arguments for the existence of God.

Topics of conversation include:

  • Anselm and the ontological argument
  • How the ontological argument can be effective today
  • Aristotle/Aquinas and the cosmological argument
  • How these medieval arguments for the existence of God can best be used in evangelism

Dr. David Hogg serves as professor of Church History and director of Library Services at Phoenix Seminary, and previously pastored a church in Raleigh, NC. Dr. Hogg holds a PhD in Medieval Theology from St. Mary’s School of Divinity at St. Andrews University in Scotland.


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Intro (00:01):

Welcome to Faith Seeking Understanding, a podcast from Phoenix Seminary—helping Christians grow in their understanding of the faith, hosted by Dr. Brian Arnold, president of Phoenix Seminary,


Brian Arnold (00:18):

Eminent philosopher Charles Taylor has famously defined secularism in our day in his book, A Secular Age. Taylor argues that in the pre-modern world it is easier to believe in God than not to believe in God. In the modern age, it’s just as easy to believe in God as not to believe in God. But in this current secular age, it’s easier not to believe in God than to believe in God. In other words, people are finding it much harder to believe that there’s a God in the modern Western world. But the very basis of the Christian faith is that God exists. He has revealed himself and he wants to be known. So as Christians in the secular world, it is important for us to have sound arguments for God’s existence. Some of the most famous arguments for the existence of God come from the middle ages, and have been used with great success since then. To help us understand these arguments for the existence of God, we have with us Dr. David Hogg, who serves as professor of Church History and director of Library Services at Phoenix Seminary. He has served in higher education for nearly 20 years, and has most recently reentered academia, after serving as a pastor for the last five years in Raleigh, North Carolina. Dr. Hogg is the only evangelical medievalist I know, having earned his PhD in Medieval Theology at St. Andrews in Scotland. Dr. Hogg, welcome to the podcast.


David Hogg (01:30):

Thank you for having me. It’s good to be here.


Brian Arnold (01:31):

So we always ask our guests one big question. Today the big question is this—how do we know God exists? And I want us to focus on the area of your expertise. So you are a world-renowned expert on Anselm of Canterbury. What I want you to do, to start off with, is not assume that people know who that is. So tell us who Anselm is. And then he famously gave us what we call the ontological argument. So then we’ll dive in. Go ahead.


David Hogg (01:56):

Yeah, sure. So Anselm was, he was most famously known as the Archbishop of Canterbury, although he himself was born in Northern Italy in 1033. And he is interesting. He, like so many people, he wasted away the early years of his life…traveled around Europe, did what, you know, students today do, take a year off after they graduate from high school or they graduate from university, and they travel Europe. He traveled Europe and began to realize, you know, maybe life should be more than just pleasing myself and living for myself. So he went and tried to find the smartest man he knew, who at the time was considered Lanfranc of Canterbury, or Lanfranc of Bec at that stage—


Brian Arnold (02:37):

Because I wasn’t alive then.


David Hogg (02:38):

Because yeah, that’s right. That’s right. So, since he did look up Brian Arnold, but he he had to cross the pond, and he thought, you know, I don’t have any way to get there. I’ve just got a small motor boat and—


Brian Arnold (02:49):

I’ll settle. Okay.


David Hogg (02:51):

So he settled for Lanfranc, and he studied with him. And he’s…and Lanfranc was at a monastery, and so Anselm became a monk. And for years he rose up through the ranks of being a monk. He was a monk, and then prior, and then abbot—that means that he was the head of the monastery. And then from there, he was so well renowned by his own writings and his own connections with so many famous people of the day, that he was an obvious choice for Archbishop of Canterbury. He didn’t want to be Archbishop of Canterbury. He famously…there’s a great story in which he rejected it quite vociferously, but at the end of the day his friends managed to convince him otherwise. And so, yeah.


Brian Arnold (03:27):

Which, it’s a good lesson for us—if we just want to say this quickly—is that’s a common tale in church history. How many people rise up the ecclesial ladder, who don’t want that. And they actually don’t. It’s not false humility. They want a life of quiet, study, reclusiveness, not the messy business of church administration and pastoring, which doesn’t seem to be as true today.


David Hogg (03:49):

No, not so much. And yeah, it’s a good question as to why. I don’t, you know—I suppose any number of reasons could be given, but Anselm was certainly the sort of man who loved that small group interaction. He loved sitting down with students and just talking about the issues of the day, and that’s where he wanted to be. He didn’t want to be the guy who had all been—there’s a lot of—Archbishop of Canterbury. In that day, I mean, today, it’s a big deal, but not actually as big as it was back then. And so for him, that was huge. It was a lot of politics as well. Which, if you’re into politics, that’s a great thing. If you’re not into politics, maybe not so much, you know? But for Anselm, he wasn’t a political maneuverer. Although Sally Vaughn has argued contrary to that. There’s kind of a disagreement from years past between Sally Vaughn and Richard Southern on this. But I tend to go with Richard Southern. I think Anselm really did prefer just the quiet life, and he didn’t want all the administration and the hoopla that goes along with holding the, basically the second highest position in the nation.


Brian Arnold (04:49):

Yet he was asking these big questions in his day, and getting students to talk about them. One of these big questions is on the existence of God. And so he writes this little book—it’s not long.


David Hogg (04:57):

It’s very short.


Brian Arnold (04:58):

The Proslogion. That’s probably why you chose to study it. You’re like—what’s the shortest work in church history? 19 pages—I’ll do it! And so he writes this a little book called the Proslogion, and he gives us what we call now the ontological argument. So define that, and kind of walk us through Anselm’s argument.


David Hogg (05:17):

Yeah. So, I mean, it’s called the ontological argument because it has to do with being, the nature of what it means to exist and so forth. And there are basically two parts to this in the Proslogion. The first is, of course, this famous statement. If you’ve ever taken a philosophy class, or if you’ve ever, you know, sat through any courses in theology, you’ve probably heard this. That, he begins by saying that “God is that than which nothing greater can be conceived.” Now, if you’ve never heard that before, you probably need to stop, pause, and think about that for awhile. It’s a strange way of talking. God is that than which nothing greater can be conceived. And that’s basically, if I could put it in layman’s terms, basically means thinking of the greatest being, in every way.


David Hogg (05:55):

And when you reach the apex of that greatest being in your mind, that can’t be surpassed or improved in any way—that’s God. So he’s at the height of everything. But the other thing to bear in mind is that, at the mid point of his book, he then turns around and says—God is not only that than which nothing greater can be conceived, God is also greater than what you can conceive. So once you think you’ve reached the apex of everything in being, like, okay, that’s gotta be God, because he’s all knowing, all powerful, you know, add up all the things you think. And he says, yeah, that’s okay, that’s…you’ve got a good concept of God. Then he turns around and says, yeah, but then he’s actually beyond that. So he’s beyond what you could even imagine.


David Hogg (06:35):

And the point of what Anselm is doing is actually to say, look, well, there’s a number of things he’s doing, but one is, he’s trying to say—look, the nature of God is such that he is what we in theology call, he is both imminent and transcendent. Imminent simply means he’s close. He’s near. Something we can relate to. We can figure this out, at least by analogy. We know, we can understand that. Transcendent means he’s way beyond where we’re at. And so Anselm is using these two approaches to God to say—look, this is who God is. He is relatable. He is close. He is near. So when we say, “God is love,” that’s a strange…to say “he is love” is strange, but we can kind of get there, because we think, well, I know what it is to love.


David Hogg (07:13):

I know what it is to be loved. So I can at least understand that—


Brian Arnold (07:16):

God is Father.


David Hogg (07:17):

God is Father, yeah. Precisely. Yeah. So that’s the imminent characteristics. But then he also wants to say, but God is also way beyond. So he talks about God as being an “ineffable light.” I mean, who knows what that is? I haven’t the foggiest idea, but anyway. Omnipresent, he’s everywhere, you know, and he’s simple. That’s a whole different conversation. But in all of this, what Anselm is trying to do, and this is what people lose, where people lose the thread a bit—and by people, I mean, it’s often scholars—they think that Anselm is talking about a being who is Supreme. And that’s the last thing Anselm wants to do. Anselm wants to introduce people to the personal God and what he’s like.


David Hogg (07:56):

So when he says, “God is that than which nothing greater can be conceived,” people immediately think, oh, that’s so abstract. But then, as he goes through his book, he says, so that means he is loving, and just, and kind, and good, and all these sorts of things. And then you begin to realize, oh, okay, well, that makes sense. I can understand. But he’s just the best of all those things. And then when he says, “God is greater than that which can be conceived,” and you think, well, okay, so what does that mean? Well, that means he is everywhere, all at the same time. Okay. I can sort of get that conceptually, but practically haven’t the foggiest idea what it means. He knows everything. He knows every thought of every human being. Eight billion people on the planet. He knows every thought, every intention, every will, every—he knows, despite, you know, Heisenberg’s complaints to the contrary, he knows where every molecule is. You know, God is…I mean, okay—that’s transcendence, that’s different.


David Hogg (08:46):

So that’s essentially his argument. Is not just let me show you that there’s a God, but more importantly, let me show you who this God is. Because at the end of the day, if you just get convinced about a Supreme being, I think Anselm’s response is—so what? Who cares? I want to know who he is, or who is this God. And when I know who he is, well, that’s going to make a difference for how I live, or how I respond to him, or what I think about him, all these sorts of things. So that’s the basics of, I think, Anselm’s…


Brian Arnold (09:16):

And so you and I both teach church history, and we teach this to our students. Inevitably, a student will say—I don’t buy that. I hear that argument, so I’m just, in my mind, conceiving that than which nothing greater can possibly be conceived. It didn’t work. Right? I tried that. Or my neighbor, who’s an atheist. I said, just think harder. And they said, this is kind of a bogus claim. So in what ways do you see this argument being helpful in our day, today? Or how can it be employed in apologetics successfully? How do we do that?


David Hogg (09:53):

Yeah. So it’s a great question. In an interesting sort of experiment, when I was studying in Scotland, I actually tried this on my neighbor, because my neighbor was lost as lost can be, not a Christian, didn’t care to be a Christian, pagan through and through. But really nice guy. We got along really well. You know, we were always in each other’s homes and, you know, enjoying tea, because, of course, you’re in Scotland. So that’s what you do. But at any rate, I thought, you know, this is really interesting, I want to try this out. But I thought, okay, I can’t give this to him in Anselm’s language. Because Anselm’s writing in the 11th century, it’s a different form of discussion, so forth. So I thought, how can I do this? And in essence, I basically started talking to him about, you know, studies, what I was doing, trying to get into it sort of carefully.


David Hogg (10:37):

I didn’t want to set this up as, you know, a fall or anything. So he said, well, tell me, okay, what really are you studying? And I said, well, you know, this guy Anselm and about God. And he said, so you really think God exists? And I thought—I’ve got him now. So I said, well, I do, I said, but let me ask you something. I said, if God were to exist, what do you think he’d be like? So in other words, just an open-ended question. And he sat back, and he said, well, I mean, so he’d have to be…he’d have to know everything. And he’d have to be, like, super powerful, way beyond, you know, all the stuff we know in the hero comics and all the rest of it. So he’d have to be basically all-powerful, and he’d have to be all-knowing, and he went on, he listed all these incredible things.


David Hogg (11:19):

And I said, okay, so that’s essentially like his nature, but what about his character? I mean, what does…what do you think he should be like? And he said, well, I’d like to think that he was, you know, that he was loving, you know, and he was kind, he started naming all these things. I said, okay, that’s really interesting. And I said, now consider this God you’ve just described. Let’s imagine he is like that, but to the highest degree possible. And he paused and he said, that would be awesome. He said, could you imagine a God who’s actually like that?


Brian Arnold (11:52):

I can.


David Hogg (11:54):

I said, well, as it happens, I can. And so what that was…I mean, from there the conversation went in different directions, but at that stage he had essentially defined, by himself, God is, you know, that which is, you know…that than which nothing greater can be conceived. He’s the best of everything.


David Hogg (12:12):

And then I said, well, wouldn’t it be great if he was totally awesome in every category? And it just blew his mind. And he thought, that would be a God beyond anything I could…you know, he almost said beyond I could imagine. And I thought—you just defined God in exactly the way Anselm has. And so the thing that intrigued me about that, the reason I wanted to try it, is I’ve always had a theory, and it’ll never be anything more than a theory until I meet Anselm in the new creation, and I tell him how to improve what he wrote. But my theory is this—Anselm, the nature of theology in the middle ages…you don’t actually get to write theology until you’ve studied the Bible for a long, long time. And monks, they’ve memorized, believe it or not, most of the Bible.


David Hogg (12:58):

They either read or listened to all 150 Psalms, all in a week. And then would start again the next week. So 52 weeks a year, you’re hitting all 150 Psalms. Every week. Like, it’s incredible. And that’s just the Psalms, forget everything else. So the Bible is in their heads. So my theory is this—I think Anselm was thinking about Romans one and Romans two. In Romans one, there…if you remember Romans one, Paul goes through and, you know, after saying greetings to the church in Rome, he says, look, there’s a lot of people out there who are sinning something terrible. And basically, Paul goes on to say, it’s not because they’re ignorant of who God is. It’s because, as he says, they’re suppressing the truth of the knowledge of God within. They know God is there, because they’ve been created in his image.


David Hogg (13:43):

They know he’s there. They’re just suppressing it. And, you know, Romans two goes on to develop that as well. But I think, in a way, Anselm thought to himself, I don’t have to prove anything to anyone, because everyone already knows this God exists, in some sense. All I need to do is find a way to kind of reach inside their heart. And because there’s already a boiling cauldron of suppression—it’s like a pot that’s boiling, and the lid wants to come off, because the creation of the pressure with the steam, but everyone keeps pressing this down who doesn’t believe, like, no, I’m not going to believe there’s a God. I mean, I know I see the universe out there, and it’s awfully impressive, and I know I see the intricacies of creation, and I know I see people who are loving and kind and generous, and where does that come from?


David Hogg (14:24):

But no, I’m going to keep pushing this away, pushing this away, denying God, denying God. And Anselm just wants to reach inside—a little bit, like I did with my neighbor—wants to reach inside, and pull the lid off, and just let the steam come out, and say, you see, that’s the kind of God you really long for. Now, let me show you that he really does exist. So I think that’s what’s going on. I think that’s why it can be so effective for people, even when they…in the form in which you read it in the Proslogion—probably not the sort of thing people are going to pick up and read while they’re sitting in the doctor’s office, waiting. But when you realize what he’s doing, I think you can take it and apply it in ways that are effective for our own day.


Brian Arnold (15:03):

I just got to say, you using the image of a cauldron over a fire is the most medieval thing I think I’ve ever heard.


David Hogg (15:11):

Yeah. Did I mention there was a witch stirring the pot at the same time?


Brian Arnold (15:15):

The picture is there. But I think it’s really helpful to understand what Paul is saying. The image of God in us longs for the Creator, and it’s going to fill the worship void in any way they can. And it’s simmering on top. I thought that was a beautiful image to use. So even in Anselm’s own day, a chap comes along and says, pretend there’s an island. And I’m picturing the most perfect island, the best beach, the right palm trees, luscious fruit, all these pieces. So it must exist then, right Anselm? If I can just imagine it, must therefore be. And so they get into a little bit of a dialogue back and forth. So how does Anselm address that response?


David Hogg (15:54):

Well, he says you silly, silly man. It’s kind of interesting. He…I think there’s a bit of frustration with Anselm, because the question is, I think, a legitimate one. It’s not just…some people have argued, oh, this is just a setup, you know, whatever. But there actually was…the guy’s name was Gaunilo, and he had actually written letters back and forth with Gaunilo. So they knew each other. And Gaunilo’s point was a good one, in a certain sense. Because if you think, well…just like if you do what I did with my neighbor, and say, you know, imagine God, then fill that—well, surely you could fill it with anything you want. But I think that’s where we, you know…as Anselm responds to Gaunilo, and the response to that basically is, okay, first of all, you need to understand when we’re talking about God, we are talking about a category of one. This is not true of anything, anywhere, anytime.


Brian Arnold (16:44):

He’s too generous. There’s no one like him.


David Hogg (16:49):

There’s no one like him. There’s absolutely no one like him. So when you say, what would God be like? And you fill it with all kinds of content, that’s very, very different than saying, well, what would an awesome vacation be like? An awesome vacation is not the same thing as God. You can’t just, you know…because the awesome vacation is just wishing—I wish there were an island with palm trees, and, you know, whatever else, and, you know, what have you. Or better yet, I wish I was in Canada, because that’s where everybody really wants to go. I think that’s…isn’t that where we’re going? I think we’re going there with that—


Brian Arnold (17:23):



David Hogg (17:23):

But at any rate, wherever it may be, it’s not in the nature of vacations to—I’ll put it this way—it’s not in the nature of vacations to exist, necessarily,


Brian Arnold (17:34):

Well, the perfect one has never existed for me.


David Hogg (17:35):

Never existed. Exactly right, you know? But it is in the nature of God to exist necessarily. Now that introduces a kind of philosophical concept of—is there a being whose existence is what philosophers call necessary? And this is an important thing to bear in mind, because one of the…you know, Thomas Aquinas, a couple hundred years later comes along, and as he comes along…Thomas Aquinas, you know, one of his arguments about the existence of God is to say, well, all right, let’s think about this for a moment. So, you know, I was here because my parents. My parents were there because of their parents. And you know, that tree was there because of a seed. And that seed was there because of a tree. And that tree was there because it was…like, you keep going back and back and back, eventually you’ve got to ask yourself the question—so where does everything…how does everything start? And of course, physicists and astronomers know this is a really tricky question, you know, and they have different ways of answering. There was a singularity. Okay, well, where does the singularity come…what is a singular—you know, where does it come from? I’ve heard, you know, that apparently there are different universes, and they all are…act like kind of membranes. And when the membranes crash together, they create a new universe. And I think,


Brian Arnold (18:39):

Well, where do the membranes come from?


David Hogg (18:40):

Where do the membranes come from?


Brian Arnold (18:42):

Aquinas is pulling off Aristotle, right? I mean, so Aristotle did these, the first mover, you know, the unmoved mover, where does that come from? Right? And we don’t have a lot of time to dive into this, but that’s called the cosmological argument. So in the middle ages, you have the ontological argument with Anselm. So for those of you who this might be new concepts, which is—how do we just think of God? It’s kind of like an a priori argument. And then you get Aquinas saying, well, there might be a different way to think about this—a posteriori, cause and effect. How do we go back to the beginning? Which I think people resonate with more in our day, today, especially we’re in such a scientific world and pressing people in the sciences, you know, maybe evolutionary biologists, to say, but what came before? You almost turn into like the obnoxious two year old—well, what came before that? What came before that? What came before that? And eventually they have to explain that they don’t know, right? It’s mystery. And I think they run into the problem of what we call infinite regress. If you can always go infinitely back into eternal matter in the past, you can never actually get to the present. You can’t actualize it. So, yeah.


David Hogg (19:43):

Yeah. And I mean, another way to think about that is, you know, like…so the way that Aquinas actually, in the cosmological argument, the way he talked about it had to do with—again, philosophical terms—he talked about potentiality and actuality. And the way I try to explain that when I’m talking with students is it’s a little bit like a pool table or a snooker table. If you play snooker, I don’t know if you—


Brian Arnold (20:04):

I do not.


David Hogg (20:04):

You do not play snooker? Oh, there you go. See, that’s your loss. But, so you imagine a pool table, with the pool, you know, the balls are there, the pockets, and all the rest of it. All of those balls have what we call potential energy, which, you know if you’ve taken physics, like, it’s not, the gravity is pulling on it, but the table is stopping it.


David Hogg (20:20):

So there’s something potential about what’s there, but it needs something else to make it action. Turn it into kinetic energy and so forth. Well, the same thing with actuality and potentially. The balls are just sitting there. They can’t do anything until somebody hits them with a cue, or lifts up the table, or there’s an earthquake, or, you know, or wind blows, or whatever. There’s got to be something else acting on. So the question becomes, you know, in the medieval terms, all right, so eventually, everything that has, you know, potential energy—we recognize that it has potentiality—can only do anything unless something that is total actuality, and has no potentiality in it whatsoever, in other words, it can move of its own accord, under its own power, with its own everything, and doesn’t require anything outside of itself to move. You need that to get everything going. So whether it’s a big bang, or membranes bashing together, or a singularity, or whether it’s, you know, the creation of planets or stars, nothing starts, nothing can become actual, until it’s stirred out of its potential. But it can only be stirred out of its potential, if something that is always actual comes along and hits the ball, or knocks the table, or does whatever. I don’t know if that makes sense?


Brian Arnold (21:30):

Yeah, absolutely. It does. And I think, you know, our time is running low, but between kind of laying out Anselm’s approach, and Aquinas’s approach, and recognizing the secular age in which we live, that making arguments for God’s existence is important. Counsel us in one or two minutes of just how we can best use these kinds of approaches in what I hope, people listening, is evangelism. Of talking to the lost.


David Hogg (21:59):

Yeah, I think…well, the first thing that I always say, is it’s really important to just listen to people and find out where they’re at. I think you need to find a…and the reason is, there’s…so an apologist named Van Til said, you know, you need to find the point of contact. That was his regular thing—what is the point of contact? And by that, he meant—what is it, that someone really cares about? To the point where you recognize, okay, now I know how to talk to them in a way that’s going to matter to them. Because other things they may not care about. So some people may, you know, somebody may care about being and existence. They’re in philosophy, they’ve taken philosophy classes. Anselm’s approach may be the very thing that they want. But it doesn’t have to be a philosophy class.


David Hogg (22:42):

It could be my neighbor in Scotland, who I simply said, imagine a God. Oh man, it would be awesome if such a God existed! Well, that’s an open door. Now I’ve discovered, oh, this guy really wants a God to exist. He’s just never known who this God is. You know, for someone else, it, it really may be that you’re in a pool hall playing pool with somebody, and you realize this thing, this matters most to them. Well, let’s talk about pool balls and, well, how they move. And so in other words, I think that the key is to figure out what matters to people. And when we know what matters to them, then we can be careful about how we talk to them. Because then we’re not wasting time talking about things they don’t care about. I mean, if I walked up to somebody on the street after this is over, and I go down there and I say, right, I’d like to talk to you about God. Okay? Let me tell you about Anselm of Canterbury in 11th century, you know…I mean, there’s nothing, you know. We’ve lost them. So I think just having that, finding out, caring enough—I’ll put it in biblical terms—loving your neighbor enough to listen to them, so that you know what they care about. And then you take what they care about, and you help them see that that really matters. But it also matters for how they should think about God


Brian Arnold (23:53):

With the assumption we can bring to the table, that as image bearers of God, as those who were created to know God, there’s that cauldron with the lid on it. And the temperature is boiling the water. And knowing which way to pry the lid open is knowing our neighbor, loving our neighbor. But using some of these arguments, whether it’s Anselm’s ontological argument, whether it’s Aquinas’s cosmological argument, we can hopefully show them that God does exist, because it is important in our day, I think, for a secularizing world to remember that there is a God.


David Hogg (24:28):



Brian Arnold (24:28):

And that they must bow their knee to him.


David Hogg (24:29):



Brian Arnold (24:30):

Well, Dr. Hogg, thank you so much for being with us today.


David Hogg (24:32):

Appreciate it. Thank you.


Outro (24:34):

Thank you for listening to the Faith Seeking Understanding podcast. If you want to grow more in your understanding of the faith, consider studying at Phoenix Seminary, where men and women are trained for Christ-centered ministry for the building up of healthy churches in Phoenix and throughout the world. Learn more at

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